No idea what this comment is about, what you said is simply correct. One has to ignore fuzzy question of how natural Tuvix's creation is, whether Tuvox and Neelix are dead or a part of Tuvix or whatever. One has to be technical: they are dead, he is alive. And if you want them back you have to kill him.
I am totally fine with Janeway's decision as long as one calls it what it is, murder.